We compared and contrasted points of concurrency in a triangle to their analogs in a tetrahedron. Certain circles and spheres associated with these points of concurrency were discussed. Cabri 3D was used to model and help visualize the properties and relationships between the various points and segments in the two-dimensional and three-dimensional cases.

Download Troy's presentation as: .pptm || zipped .pptm || .pdf || .mov Note: If you view either the PDF or MOV versions of this file, the animated 3D features will not display. You may not be able to manipulate the embedded figures unless you have Cabri 3D installed on your computer or at least the appropriate plugin.